Technical Field
The embodiments described herein relate generally to room monitoring systems, and more specifically to systems, methods, and modes for determining audio calibration specifications of a room utilizing a minimum amount of equipment.
Background Art
Currently available ambient noise sensor systems (ANSS) 100, as shown in FIG. 1, use both speaker 102 and microphone (mic) 104 to ascertain the noise level in acoustic space 114. Also shown in FIG. 1 as part of currently available noise sensor system 100 are ambient noise cancellation circuit (ANC) 110 (to determine noise levels and provide the output signal), combined digital-to-analog converter/amplifier (DAC) 106 (to convert the digitized audio output of ANC 110 to an analog signal and amplify the same), and combined analog-to-digital converter/pre-amplifier 108 (to receive the analog signal from mic 104, amplify it, and then convert the amplified analog signal to a digital signal). Speaker 102 broadcasts messages/announcements, and mic 104 can be used to measure the ambient noise. The ambient noise can be detected/measured just prior to when an announcement is to be played over speaker 102 and measured. Based on the measured amount of ambient noise, gain is then added to amplifier 106 by digital commands to increase the output of amplifier 106. For example, if the announcement was typically to be broadcast at 60 decibels (dB) sound pressure level (SPL), and it was determined that there is about 10 dB SPL noise level as measured by ANSS 100, then some gain, perhaps about 10 dB, can be added to the gain of amplifier 106 such that the output SPL is now set to be about 70 dB, instead of 60 dB; thus, a constant signal-to-noise ratio (SNR) is maintained. Such ANSS 100 involves multiple components; in relatively large rooms, or enterprise locations with a significant amount of rooms, the extra components can drive up the costs when implementing ANSS 100.
Accordingly, a need has arisen for systems, methods, and modes for determining ambient audio conditions utilizing a minimum amount of equipment.
As those of skill in the art can further appreciate, it is desirable to “tune” a room spectrally; that is, when using an audio system, to calibrate the amplifiers and mixers such that spectrally the response of the room is substantially flat. What is meant by “flat” is that there are neither significant valleys nor peaks in the spectral response of the room. All rooms, to some extent, will affect the frequencies of audio signals broadcast in the room in either a constructive manner, or destructive manner. That is, if a spectrally flat signal were input to the amplifier system, and a spectral response from the speakers were obtained, at some frequencies there would be valleys—meaning points of greater attenuation, and in other places there would be peaks, meaning points in which constructive interference had occurred.
Currently available audio calibration systems utilize separate spectrum analyzers and pink noise generators. As those of skill in the art can appreciate, pink noise or “1/f” noise is a signal or process with a frequency spectrum such that the power spectral density (energy or power per frequency interval) is inversely proportional to the frequency of the signal. In pink noise, each octave (halving/doubling in frequency) carries an equal amount of noise energy. The name arises from the pink appearance of visible light with this power spectrum. This is in contrast with white noise, which has equal intensity per frequency interval.
Currently available audio calibration systems utilize multiple devices including noise generators, spectrum analyzers and other devices.